The present circuitry pertains to fuzes for use with projectiles and is especially concerned with timing of the fuze to prevent early detonation thereof. Early detonation of a fuze can be caused by a variety of failures of the fuze electronic timing circuit or through inadvertent human error in the setting of the desired time. In prior state of the art circuitry, redundant systems involving ANDing the outputs of two identical systems is utilized to check the operation of the circuitry. However, this design results in a large amount of circuitry to accommodate the complete duplication of all circuits. Further duplication of all circuits results in an excessive power drain. In projectiles of the type discussed herein, it is desirable to utilize power from a storage capacitor that is charged by a setback generator at firing. This capacitor's size is a function of power drain, making the capacitor very large for fuzes with much duplicated circuitry. The combined size of the duplicated circuitry and its excessively large storage capacitor would be prohibitive for projectile fuzing.